The present invention concerns a zooming optical control device and, more specifically, it relates to a zooming optical system control device having a zooming optical system which comprises a zooming lens group, a macro lens group and a focusing lens group disposed on one identical optical axis, and which can optionally be set to one of a plurality of regions such as a zooming region capable of varying the focal length by the zooming lens group, a macro region capable of macro photographing by the macro lens group and a containment region for containing each of the lens groups into a predetermined position respectively.
Electronic constitutions or electric driving systems have been introduced remarkably in recent years for camera main bodies and photographing lenses used for the cameras. For instance, in the photographing lenses such that lens groups constituting them are adapted to be driven by a motor, etc. and set into each of a plurality of regions such as a zooming region capable of varying the focal length, a macro region capable of macro photographing and a containment region for rendering the structure compact when they are not used by a one-touch switching operation.
While on the other hand, along with the cost reduction of one chip microcomputers (hereinafter simply referred to as "CPU"), various control operations have now been conducted collectively by the CPU, such as control for the change of the focal length in the zooming region, particularly, control for the compensation of shift in a varifocal lens that generates the deviation for the imaging position (shift) accompanying the change of the focal length in the photographing lenses, as well as control for various automated camera operations, e.g., automatic focusing, automatic exposure, automatic film loading and unloading in camera main bodies.
By the way, although it is possible to control the photographing lenses independently by a CPU incorporated into the lenses per se, it has generally been constituted to control such photographing lenses by the CPU disposed to the camera main body in view of the economical reason. Accordingly, operation switches actuated by a camera user as described above and status detection switches for detecting the state of various mechanical sections of the camera main body and the photographing lenses, etc. are connected to the input ports for recognizing the external state required upon executing various controls by the CPU. However, since the number of the input ports is restricted, while it is different depending on the type of CPU, it is desirable that the number of switches connected to the input ports is as less as possible in order to cope with the extensibility for various control operations, change for the specifications of the camera and the photographing lenses, etc.
By the way, in the photographing lenses having a plurality of regions described above, means are necessary for the CPU to recognize which of the regions the lens group is situated to (for example, switch). Specifically, there may be considered such a means that several stripes of region patterns each having a combination of conductor portions and insulator portions are disposed in a plane, and an electrical brush is moved under sliding contact with the region distinguishing patterns along with the movement of the lens group, so that the region can be distinguished depending on the manner of the combination of the conductor portion and the insulator portion. However, in a case where the pattern is constituted with three stripes which is the least possible number considering the restriction for the number of the input ports as described above and where a resistor body is disposed for detecting the change of the focal length within the zooming region to the region distinguishing pattern, there has been a problem that a nondistinguishing section is formed to a portion of the pattern. Further, in such a constitution not using a mechanical stopper, there has been a problem of over-run in a case of stopping the lens group at one end of a region that the lens group can not be stopped at a correct stop position but intrudes into other adjacent region by residual rotation of a motor even after the disconnection of power supply to the motor for driving the lens group.
By the way, in a case where a containment region and a macro region are disposed in adjacent with both ends of a zooming region, for example, the zooming operation for changing the focal length has generally been actuated by the operation of a zoom switching or changing switch, etc. and as the operation is continued, the lens groups finally arrives at the end of the zooming region. Then, when the switch operation is continued further, the lens group passes over the end and intrudes into other region. In order to prevent this, stoppers are required at both ends of the zooming region for inhibiting this disadvantage. The stopper has been constituted mechanically so far. However, in a case where the containment region and the macro region are disposed in adjacent with the both ends of the zooming region, if the position of the lens group situated in the zooming region is changed to the macro region or the containment region, the stopper has to be released automatically. Accordingly, there have been problems that a release mechanism is required. The control of the mechanism complicates the constitution and generates rattling inherent to the mechanical members and, further, the rattling is increased with the elapse of time to make the operation instable. Furthermore, there is also a problem that the scale is inevitably increased since it is mechanical constitution, which provides an economical disadvantage in combination with the complicated structure as described above.
In addition, although it is possible to release the stopper by the manual operation, this causes another problem of reducing the operationability.
While on the other hand, the conventional photographing lenses comprise each of the lens groups, that is, the zooming lens group, the macro lens group and the focusing lens group and adapted to change the setting region by the movement of the zooming lens group, further change the focal length in the zooming region and enable the focusing operation by moving a portion of the zooming lens group independently from the zooming operation for changing the focal length. In a so-called vari-focal lens, the focusing position to an identical object in the zooming region varies depending on the focal length and, generally, it draws a hyperbolic curve. More specifically, taking the infinite position (.infin.) on an optical axis corresponding to the infinite object distance as a standard (invariable), the focusing position at the nearest position and on the side of the nearest position on the optical axis corresponding to the nearest object distance forms a focusing curve represented by such a hyperbola that the delivery amount from the .infin. position is increased as the focal length approaches the lowest focal point (TELE) side and the delivery amount is decreased as it approaches the shortest focal point (WIDE) side. Accordingly, the movable region of the focusing lens group is between the .infin. position and the nearest position as described above. Then, a stopper of a shape along with the focusing curve in the equivalent manner is formed for inhibiting the movement of the focusing lens group at the terminal end on the nearest position side of the movable region, whereas a stopper of a shape invariable to the change of the focal length, that is, of a linear shape is formed at the .infin. position. Accordingly, in a case where the focusing lens is near the nearest position on the TELE side described above, since the focusing lens group is also driven as a portion of the zooming lens by the zooming operation and the region changing operation for changing the setting region, if the setting region is being to be changed from the zooming region to the containment region assuming that the containment region is in adjacent with the WIDE side, a portion of the zooming lens group comes to hit and abut against the hyperbola stopper to result in a problem that the region changing operation is inhibited at the midway of the zooming region.